Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a dis...Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed. Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when butt gap is appropriate, that is from 0. 1 to 0. 15 mm, molten metals formed on two workpiece uplift and grow up first, then are fused and form uniform molten pool finally.展开更多
The superplasticity of Ti-6Al-4V butt-welded plates by laser beam welding(LBW)was studied in virtue of hot tensile tests and superplastic bulging tests.Furthermore,microstructural evolution of weld metal upon superpla...The superplasticity of Ti-6Al-4V butt-welded plates by laser beam welding(LBW)was studied in virtue of hot tensile tests and superplastic bulging tests.Furthermore,microstructural evolution of weld metal upon superplastic forming was systematically analyzed via metallographical tests and scanning electron microscope(SEM).The relation between the microstructure of weld metal and its superplastic ability was discussed.The experimental results show that Ti-6Al-4V butt-welded plates by LBW possess superplasticity.The maximum elongation is up to 154%and the maximum bulge height can be up to 1.81 times the internal radius of the female die.There is an optimum value of the bulge height for bulging gas pressure.展开更多
A multi- pumose simulation method for the roll- formign is proposed. The forming pro- cesses of welded pipes are systematically simulated by using the method. The three-dimensional cu rved surfaces of sheet...A multi- pumose simulation method for the roll- formign is proposed. The forming pro- cesses of welded pipes are systematically simulated by using the method. The three-dimensional cu rved surfaces of sheet metals in forming processes are mathema tically expressed by using the shape fonction S(X) which represents flow pattern of each part of sheet metal. Through optimis- ing t e parameter n in s(X), the best approximation of the deformation of sheet metal is derived and the minimum power of deformation is obtained. A mathematical procedure of this analysis is systematically foimulated. The simulation method can be applied to the analysis and simulation for various roll- forming processes of welded pipes observed in commercial production line.展开更多
Crimping is used in production of large diameter submerged-arc welding pipes. Many researches are focused on crimping in certain manufacturing mode of welding pipe. The application scopes of research achievements beco...Crimping is used in production of large diameter submerged-arc welding pipes. Many researches are focused on crimping in certain manufacturing mode of welding pipe. The application scopes of research achievements become limited due to lack of uniformity in theoretical analysis. In order to propose a crimping prediction method in order to control forming quality, the theory model of crimping based on elastic-plastic mechanics is established. The main technical parameters are determined by theoretical analysis, including length of crimping, base radius of punch, terminal angle of punch, base radius of die, terminal angle of die and horizontal distance between punch and die. In addition, a method used to evaluate the forming quality is presented, which investigates the bending angle after springback, forming force, straight edge length and equivalent radius of curvature. In order to investigate the effects of technical parameters on forming quality, a two-dimensional finite element model is established by finite element software ABAQUS. The finite element model is verified in that its shapes error is less than 5% by comparable experiments, which shows that their geometric precision meets demand. The crimping characteristics is obtained, such as the distribution of stress and strain and the changes of forming force, and the relation curves of technical parameters on forming quality are given by simulation analysis. The sensitivity analysis indicates that the effects of length of crimping, technical parameters of punch on forming quality are significant. In particular, the data from simulation analysis are regressed by response surface method (RSM) to establish prediction model. The feasible technical parameters are obtained from the prediction model. This method presented provides a new thought used to design technical parameters of crimping forming and makes a basis for improving crimping forming quality.展开更多
Friction element welding technology is rich of flow drill screws combined with friction welding technology and is developed for the hot-forming steel plate and aluminum alloy welding of car body-in-white.In this paper...Friction element welding technology is rich of flow drill screws combined with friction welding technology and is developed for the hot-forming steel plate and aluminum alloy welding of car body-in-white.In this paper,the principle of RES welding technology,equipment,technical characteristics,application condition and welding parameters are analyzed systematically.Moreover,the changing laws of welding parameters and welded joint quality control standards are described,which provides the necessary technical support for safety and light-weight car body design requirements.This study has high practical application value,and enriches the automobile body joining technology.展开更多
文摘Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed. Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when butt gap is appropriate, that is from 0. 1 to 0. 15 mm, molten metals formed on two workpiece uplift and grow up first, then are fused and form uniform molten pool finally.
基金Project(50775052)supported by the National Natural Science Foundation of China。
文摘The superplasticity of Ti-6Al-4V butt-welded plates by laser beam welding(LBW)was studied in virtue of hot tensile tests and superplastic bulging tests.Furthermore,microstructural evolution of weld metal upon superplastic forming was systematically analyzed via metallographical tests and scanning electron microscope(SEM).The relation between the microstructure of weld metal and its superplastic ability was discussed.The experimental results show that Ti-6Al-4V butt-welded plates by LBW possess superplasticity.The maximum elongation is up to 154%and the maximum bulge height can be up to 1.81 times the internal radius of the female die.There is an optimum value of the bulge height for bulging gas pressure.
文摘A multi- pumose simulation method for the roll- formign is proposed. The forming pro- cesses of welded pipes are systematically simulated by using the method. The three-dimensional cu rved surfaces of sheet metals in forming processes are mathema tically expressed by using the shape fonction S(X) which represents flow pattern of each part of sheet metal. Through optimis- ing t e parameter n in s(X), the best approximation of the deformation of sheet metal is derived and the minimum power of deformation is obtained. A mathematical procedure of this analysis is systematically foimulated. The simulation method can be applied to the analysis and simulation for various roll- forming processes of welded pipes observed in commercial production line.
基金supported by Hebei Excellent Youth Fund of Science and Technology Research for Colleges and Universities of China(Grant NoY2012035)
文摘Crimping is used in production of large diameter submerged-arc welding pipes. Many researches are focused on crimping in certain manufacturing mode of welding pipe. The application scopes of research achievements become limited due to lack of uniformity in theoretical analysis. In order to propose a crimping prediction method in order to control forming quality, the theory model of crimping based on elastic-plastic mechanics is established. The main technical parameters are determined by theoretical analysis, including length of crimping, base radius of punch, terminal angle of punch, base radius of die, terminal angle of die and horizontal distance between punch and die. In addition, a method used to evaluate the forming quality is presented, which investigates the bending angle after springback, forming force, straight edge length and equivalent radius of curvature. In order to investigate the effects of technical parameters on forming quality, a two-dimensional finite element model is established by finite element software ABAQUS. The finite element model is verified in that its shapes error is less than 5% by comparable experiments, which shows that their geometric precision meets demand. The crimping characteristics is obtained, such as the distribution of stress and strain and the changes of forming force, and the relation curves of technical parameters on forming quality are given by simulation analysis. The sensitivity analysis indicates that the effects of length of crimping, technical parameters of punch on forming quality are significant. In particular, the data from simulation analysis are regressed by response surface method (RSM) to establish prediction model. The feasible technical parameters are obtained from the prediction model. This method presented provides a new thought used to design technical parameters of crimping forming and makes a basis for improving crimping forming quality.
文摘Friction element welding technology is rich of flow drill screws combined with friction welding technology and is developed for the hot-forming steel plate and aluminum alloy welding of car body-in-white.In this paper,the principle of RES welding technology,equipment,technical characteristics,application condition and welding parameters are analyzed systematically.Moreover,the changing laws of welding parameters and welded joint quality control standards are described,which provides the necessary technical support for safety and light-weight car body design requirements.This study has high practical application value,and enriches the automobile body joining technology.
基金National Science Foundation for Young Scientists of China(Nos.12102427,12102202)Chinese Innovation and Entrepreneurship Training Program for College Students(No.202210288112X)。